This invention relates in general to an electrical switch construction and in particular to a new and useful electrical switch which has a movable plunger which operates a movable slide containing movable contacts which engage respective fixed contacts and including a resetting member which is actuated by the movement of the plunger to cause a corresponding movement of the slide in an opposite direction.
A switch similar to the inventive switch is disclosed, for example, in German OS No. 31 25 816 (U.S. Pat. No. 4,442,328). A preferred embodiment of this prior art switch is an electrical switch having a bracket-shaped snap spring, with the plane of the spring extending obliquely to the plane of displacement of the slide and the operating plunger, and in the two end positions, being operatively inclined relative to a neutral position. A displacement of the operating plunger causes the spring to tilt in the direction of the neutral position. Such switches are employed particularly for closing or opening DC circuits. They are not limited to such use however. A relatively strong snap spring may be provided to obtain a strong resetting force. Also, a return spring may be provided acting on the slide, only such a spring must be substantially weaker since it is tensioned during the switching operation.
It happens from time to time, that the contacts melt together so that a particularly strong resetting force is needed which cannot be produced by the springs. Another possible trouble is that if a spring breaks, and, particularly, with the movable contacts sticking to the fixed ones at the same time, opening of the contacts becomes impossible.